Preparation Of Quinoa Ferulic Acid Starch Esters And The Antioxidant And Digestive Properties Of Its Stable Pickering Emulsion

Quinoa starch is a small particle starch with excellent structural and interfacial properties,and has excellent structural units for building Pickering emulsions.This project used quinoa as a raw material,extracted quinoa starch by alkaline method,and double esterification modification of quinoa starch,optimized the optimal catalytic conditions of quinoa ferulic acid starch through experiments.The modified quinoa starch esters are used to stabilize Pickering emulsion,which is suitable as a surfactant for Pickering emulsion.Ferulic acid modified quinoa starch ester has antioxidant activity.Finally,nanoparticles with good interfacial stability were applied to the construction of resveratrol emulsion,and the antioxidative and digestive properties of resveratrol embedded in the emulsion were explored.The main research contents were as follows:1.This article explored the best process for the synthesis of ferulic acid starch esters by three kinds of lipases(candida lipase,porcine pancreatic lipase,Novozym435 lipase).The optimal reaction conditions for each enzyme were determined by examining the enzyme addition amount,reaction time,reaction temperature,and reaction pH: The optimal enzyme addition amount of Candida lipase was 7.0%,the reaction time was 5.0 h,the reaction temperature was 45 ?,the reaction pH was 8.0,and the degree of substitution was 0.062% at the highest;The optimal amount of porcine pancreatic lipase was 7.0%,the reaction time was 5.0 h,the reaction temperature was 35 ?,the reaction pH was 7.0,and the degree of substitution was 0.12% at the highest;Novozym435 lipase has the best enzyme addition amount of 4%,reaction time of 5.0 h,reaction temperature of 80 ?,reaction pH of 7.0,and the highest degree of substitution was 0.64%.2.The structure of ferulic acid quinoa starch ester was characterized by nuclear magnetic resonance(1H NMR),infrared spectrometer(FT-IR),X-ray diffraction(XRD),scanning electron microscopy(SEM)and other analytical methods.The research results found that the ferulic acid monomer was successfully grafted to the skeleton of quinoa starch;the starch ester of ferulic acid lost the original A structure of the original quinoa starch,and the amorphous area increased;The surface of quinoa starch granules became rough and there were some agglomerates;The higher the degree of substitution,the smaller the particle size and contact angle of the starch,but the surface tension value increased.These data indicated that the starch particles of ferulic acid can be used to stabilize Pickering emulsions.3.By characterizing the structure of the Pickering emulsion,the quinoa ferulic acid starch nanoparticles could significantly improve the physical stability of the resveratrol Pickering emulsion during storage.The addition of ferulic acid significantly improved the stability of resveratrol.The results showed that the fermented starch ferulate stabilized Pickering emulsions catalyzed by different lipases were oil-in-water,the emulsion droplets were dense and the size was uniform;The higher the degree of substitution,the lower the particle size and the Z-potential of the ferulic acid starch ester.4.Antioxidant and digestive properties and regularity of resveratrol loaded with Pickering emulsion.Grafted ferulic acid starch ester particles stabilized Pickering emulsion with better oxidation resistance,and its stable Pickering emulsion retained more resveratrol in the emulsion after simulated in vitro digestion,Thereby,the release rate of resveratrol are high,and the protective effect on resveratrol is better.